The present invention relates to an optical pickup device for use in an optical record/reproduction apparatus such as a compact disk player.
In a compact disk, an information signal is recorded in a track continuously formed from an inside circumference to an outside circumference of the disk. In order to continuously reproduce the signal from the rotating disk, such an arrangement is required that an optical pickup mounted to the optical pickup device is adapted to move radially reciprocally over a base stand. For this, the base stand has a guide section disposed thereon for guiding the optical pickup radially of the compact disk whereas the optical pickup has an engagement portion which slidably engages with the guide section. Further disposed on the base stand is a drive means for reciprocally driving the optical pickup along the guide section. This optical pickup device is arranged as shown in FIGS. 7 and 8.
In FIGS. 7 and 8, a reference numeral 20 denotes the optical pickup; 5 the drive means for driving the optical pickup 20 radially of the compact disk (a drive shaft portion thereof is shown in FIG. 7); 4 the base stand; 10 a rack provided to the optical pickup 20; and 6 and 7 relay gears for reduction transfer of drive force to the rack 10. A guide shaft 23 is retained by retaining portions 25, 26 disposed on the base stand 4, and is fixed in position by means of a fixing screw 27. A guide section 24 extends on the base stand 4 in a parallel and opposed relation to the guide shaft 23. The guide shaft 23 extends through an engagement portion 21 of the optical pickup 20 whereas the guide section 24 is engaged with an engagement portion 22 of the optical pickup 20.
In this arrangement, the drive means 5 controlled by a servo circuit (not shown) causes, via the relay gears 6 and 7, the optical pickup 20 to reciprocate radially of a compact disk for reproducing a signal recorded in the compact disk.
More recently, a demand exists for compact disk reproduction apparatuses featuring even lower costs and higher reliability. Above all, there is a need for an optical pickup device of low-cost type, the device accounting for a particularly great cost ratio of the compact disk reproduction apparatus.
However, the conventional optical pickup device is arranged such that the guide shaft 23 extends through the engagement portion 21 of the optical pickup 20. Accordingly, the device is assembled in a manner that the guide shaft 23 penetrating the engagement portion 21 is firstly assembled to the retaining portions 25, 26 placed on the base stand 4 and then the retaining portion 25 is fixed in position by the fixing screw 27 for fixedly retaining the guide shaft on the base stand 4. This arrangement requires not only the base stand 4 provided with the retaining portions 25, 26 but also the guide shaft 23 and the fixing screw 27 for guiding the engagement portion 21 of the optical pickup 20. Hence, the large number of components are required and the assembly operation becomes complicated. This poses a problem that it is difficult to offer a low-cost optical pickup device.
In view of the foregoing, an object of the invention is to provide an optical pickup device featuring a reduced number of components and improved workability in order for realizing cost reduction and improved product quality.
For achieving the above object, an optical pickup device according to the invention comprises an object lens, an actuator for movably retaining the object lens, a mount base for tiltably retaining the actuator relative to an optical axis passing through a central portion of the object lens, a base stand on which the actuator and the mount base are mounted, a first guide section having a sectional form to stand upright from the base stand and extending along a radial direction of an optical disk for guiding the mount base radially of the optical disk, a second guide section having a sectional form to stand upright from the base stand and extending along the radial direction of the optical disk for guiding the mount base radially of the optical disk, a first engagement portion which provided on the mount base and adapted to engage with the first guide section for sliding along the radial direction of the optical disk, a second engagement portion provided on the mount base and adapted to engage with the second guide section for sliding along the radial direction of the optical disk, and drive means for reciprocally driving the mount base radially of the compact disk, characterized in that the mount base is arranged to move radially of the compact disk with the first and second engagement portions thereof being positioned to face an end of the first guide section and an end of the second guide section, respectively, so that the first and second engagement portions of the mount base can be brought into engagement with the first and second guide sections of the base stand.
This reduces the number of components and improves the workability, and thereby provide the optical pickup device featuring the reduced costs and improved product quality.
In a first aspect of the invention, the optical pickup device comprises an object lens; an actuator for movably retaining the object lens; a mount base for inclinably retaining the actuator relative to an optical axis passing through a central portion of the object lens; a base stand on which the actuator and the mount base are mounted; a first guide section having a sectional form to stand upright from the base stand and extending along a radial direction of an optical disk for guiding the mount base radially of the optical disk; a second guide section having a sectional form to stand upright from the base stand and extending along the radial direction of the optical disk for guiding the mount base radially of the optical disk; a first engagement portion which is provided at the mount base and engages with the first guide section for sliding movement radially of the optical disk; a second engagement portion which is provided at the mount base and engages with the second guide section for sliding movement radially of the optical disk; and drive means for reciprocally driving the mount base radially of the compact disk, wherein the mount base has a mountable arrangement in which the mount base is positioned to present its first and second engagement portions to an end of the first guide section and an end of the second guide section of the base stand, respectively, and moved radially of the compact disk for bringing the first and second engagement portions of the mount base into engagement with the first and second guide sections.
This arrangement permits the base stand with the first and second guide sections mounted thereon to be assembled together with the mount base, thereby simplifying the assembly operation.
In a second aspect of the invention, the optical pickup device according to the first aspect is characterized in that the first and second guide sections are integrally formed with the base stand into one body.
This arrangement contributes to reducing the number of components and dispenses with the step for attaching the first and second guide sections to the base stand. Thus, the assembly operation is further simplified.
In a third aspect of the invention, a production method of pickup device components for use in an optical pickup device, which include: a mount base for tiltably retaining an actuator; a base stand on which the actuator and the mount base are mounted; a first guide section having a sectional form to stand upright from the base stand and extending along a radial direction of an optical disk for guiding the mount base radially of the optical disk; a second guide section having a sectional form to stand upright from the base stand and extending along the radial direction of the optical disk for guiding the mount base radially of the optical disk; a first engagement portion provided on the mount base and adapted to engage with the first guide section for sliding radially of the optical disk; and a second guide section provided on the mount base and adapted to engage with the second guide section for sliding radially of the optical disk, wherein said method comprises the steps of: integrally forming all of the base stand having the first guide section and the second guide section mounted thereon, and the mount base provided with the first engagement portion and the second engagement portion, by using a same single mold; subsequently, separating said base stand and said mount base from each other; and obtaining the base stand integrally formed with the first and second guide sections, and the mount base integrally formed with the first and second engagement portions.
This method permits the base stand with the first and second guide sections and the mount base with the first and second engagement portions to be all formed at a time using a same single mold, whereby the production efficiency is improved. In this case, the components may be formed of a resin material or a sheet metal using the same single mold.
As described above, the arrangement of the invention is such that the first and second guide sections individually stand upright from the base stand, and the first and second engagement portions of the mount base are brought into slidable engagement with the respective guide sections, whereby the mount base provided with the optical pickup can be assembled directly onto the base stand having the guide sections fixed thereon. Hence, the assembly operation is simplified and the operation efficiency is enhanced. In addition, the number of components is reduced by integrally forming the first and second guide sections and the base stand into one body. As a result, the production cost is reduced and the product quality is improved.